#define ZIPLIST_TAIL_OFFSET(zl) (*((zl)+sizeof(unsigned int)))
#define ZIPLIST_LENGTH(zl) (*((zl)+2*sizeof(unsigned int)))
#define ZIPLIST_HEADER_SIZE (2*sizeof(unsigned int)+1)
+#define ZIPLIST_ENTRY_HEAD(zl) ((zl)+ZIPLIST_HEADER_SIZE)
+#define ZIPLIST_ENTRY_TAIL(zl) ((zl)+ZIPLIST_TAIL_OFFSET(zl))
+#define ZIPLIST_ENTRY_END(zl) ((zl)+ZIPLIST_BYTES(zl)-1)
#define ZIPLIST_INCR_LENGTH(zl,incr) { \
if (ZIPLIST_LENGTH(zl) < ZIP_BIGLEN) ZIPLIST_LENGTH(zl)+=incr; }
return len;
}
+/* Decode the length of the previous element stored at "p". */
+static unsigned int zipPrevDecodeLength(unsigned char *p, unsigned int *lensize) {
+ unsigned int len = *p;
+ if (len < ZIP_BIGLEN) {
+ if (lensize) *lensize = 1;
+ } else {
+ if (lensize) *lensize = 1+sizeof(len);
+ memcpy(&len,p+1,sizeof(len));
+ }
+ return len;
+}
+
+/* Encode the length of the previous entry and write it to "p". Return the
+ * number of bytes needed to encode this length if "p" is NULL. */
+static unsigned int zipPrevEncodeLength(unsigned char *p, unsigned int len) {
+ if (p == NULL) {
+ return (len < ZIP_BIGLEN) ? 1 : sizeof(len)+1;
+ } else {
+ if (len < ZIP_BIGLEN) {
+ p[0] = len;
+ return 1;
+ } else {
+ p[0] = ZIP_BIGLEN;
+ memcpy(p+1,&len,sizeof(len));
+ return 1+sizeof(len);
+ }
+ }
+}
+
/* Return the difference in number of bytes needed to store the new length
* "len" on the entry pointed to by "p". */
static int zipPrevLenByteDiff(unsigned char *p, unsigned int len) {
unsigned int prevlensize;
- zipDecodeLength(p,&prevlensize);
- return zipEncodeLength(NULL,ZIP_ENC_RAW,len)-prevlensize;
+ zipPrevDecodeLength(p,&prevlensize);
+ return zipPrevEncodeLength(NULL,len)-prevlensize;
}
/* Check if string pointed to by 'entry' can be encoded as an integer.
* Stores the integer value in 'v' and its encoding in 'encoding'.
* Warning: this function requires a NULL-terminated string! */
-static int zipTryEncoding(unsigned char *entry, long long *v, char *encoding) {
+static int zipTryEncoding(char *entry, long long *v, char *encoding) {
long long value;
char *eptr;
if (entry[0] == '-' || (entry[0] >= '0' && entry[0] <= '9')) {
- value = strtoll((char*)entry,&eptr,10);
+ value = strtoll(entry,&eptr,10);
if (eptr[0] != '\0') return 0;
if (value >= SHRT_MIN && value <= SHRT_MAX) {
*encoding = ZIP_ENC_SHORT;
/* Return a struct with all information about an entry. */
static zlentry zipEntry(unsigned char *p) {
zlentry e;
- e.prevrawlen = zipDecodeLength(p,&e.prevrawlensize);
+ e.prevrawlen = zipPrevDecodeLength(p,&e.prevrawlensize);
e.len = zipDecodeLength(p+e.prevrawlensize,&e.lensize);
e.headersize = e.prevrawlensize+e.lensize;
e.encoding = ZIP_ENCODING(p+e.prevrawlensize);
return zl;
}
-static unsigned char *ziplistHead(unsigned char *zl) {
- return zl+ZIPLIST_HEADER_SIZE;
-}
-
-static unsigned char *ziplistTail(unsigned char *zl) {
- unsigned char *p, *q;
- p = q = ziplistHead(zl);
- while (*p != ZIP_END) {
- q = p;
- p += zipRawEntryLength(p);
- }
- return q;
-
/* Delete "num" entries, starting at "p". Returns pointer to the ziplist. */
static unsigned char *__ziplistDelete(unsigned char *zl, unsigned char *p, int num) {
unsigned int i, totlen, deleted = 0;
* prevlen. Note that we can always store this length because
* it was previously stored by an entry that is being deleted. */
nextdiff = zipPrevLenByteDiff(p,first.prevrawlen);
- zipEncodeLength(p-nextdiff,ZIP_ENC_RAW,first.prevrawlen);
+ zipPrevEncodeLength(p-nextdiff,first.prevrawlen);
/* Update offset for tail */
ZIPLIST_TAIL_OFFSET(zl) -= totlen+nextdiff;
return zl;
}
-unsigned char *ziplistPush(unsigned char *zl, unsigned char *entry, unsigned int elen, int where) {
- unsigned int curlen = ZIPLIST_BYTES(zl), reqlen, prevlen;
- unsigned char *p, *curtail;
+/* Insert item at "p". */
+static unsigned char *__ziplistInsert(unsigned char *zl, unsigned char *p, char *s, unsigned int slen) {
+ unsigned int curlen = ZIPLIST_BYTES(zl), reqlen, prevlen = 0;
+ unsigned int offset, nextdiff = 0;
+ unsigned char *tail;
char encoding = ZIP_ENC_RAW;
long long value;
+ zlentry entry;
- /* We need to store the length of the current tail when the list
- * is non-empty and we push at the tail. */
- curtail = zl+ZIPLIST_TAIL_OFFSET(zl);
- if (where == ZIPLIST_TAIL && curtail[0] != ZIP_END) {
- prevlen = zipRawEntryLength(curtail);
+ /* Find out prevlen for the entry that is inserted. */
+ if (p[0] != ZIP_END) {
+ entry = zipEntry(p);
+ prevlen = entry.prevrawlen;
} else {
- prevlen = 0;
+ tail = ZIPLIST_ENTRY_TAIL(zl);
+ if (tail[0] != ZIP_END) {
+ prevlen = zipRawEntryLength(tail);
+ }
}
/* See if the entry can be encoded */
- if (zipTryEncoding(entry,&value,&encoding)) {
+ if (zipTryEncoding(s,&value,&encoding)) {
reqlen = zipEncodingSize(encoding);
} else {
- reqlen = elen;
+ reqlen = slen;
}
/* We need space for both the length of the previous entry and
* the length of the payload. */
- reqlen += zipEncodeLength(NULL,ZIP_ENC_RAW,prevlen);
- reqlen += zipEncodeLength(NULL,encoding,elen);
-
- /* Resize the ziplist and move if needed */
- zl = ziplistResize(zl,curlen+reqlen);
- if (where == ZIPLIST_HEAD) {
- p = zl+ZIPLIST_HEADER_SIZE;
- if (*p != ZIP_END) {
- /* Subtract one because of the ZIP_END bytes */
- memmove(p+reqlen,p,curlen-ZIPLIST_HEADER_SIZE-1);
- }
+ reqlen += zipPrevEncodeLength(NULL,prevlen);
+ reqlen += zipEncodeLength(NULL,encoding,slen);
+
+ /* When the insert position is not equal to the tail, we need to
+ * make sure that the next entry can hold this entry's length in
+ * its prevlen field. */
+ nextdiff = (p[0] != ZIP_END) ? zipPrevLenByteDiff(p,reqlen) : 0;
+
+ /* Store offset because a realloc may change the address of zl. */
+ offset = p-zl;
+ zl = ziplistResize(zl,curlen+reqlen+nextdiff);
+ p = zl+offset;
+
+ /* Apply memory move when necessary and update tail offset. */
+ if (p[0] != ZIP_END) {
+ /* Subtract one because of the ZIP_END bytes */
+ memmove(p+reqlen,p-nextdiff,curlen-offset-1+nextdiff);
+ /* Encode this entry's raw length in the next entry. */
+ zipPrevEncodeLength(p+reqlen,reqlen);
+ /* Update offset for tail */
+ ZIPLIST_TAIL_OFFSET(zl) += reqlen+nextdiff;
} else {
- p = zl+curlen-1;
- }
-
- /* Update tail offset if this is not the first element */
- if (curtail[0] != ZIP_END) {
- if (where == ZIPLIST_HEAD) {
- ZIPLIST_TAIL_OFFSET(zl) += reqlen;
- } else {
- ZIPLIST_TAIL_OFFSET(zl) += prevlen;
- }
+ /* This element will be the new tail. */
+ ZIPLIST_TAIL_OFFSET(zl) = p-zl;
}
/* Write the entry */
- p += zipEncodeLength(p,ZIP_ENC_RAW,prevlen);
- p += zipEncodeLength(p,encoding,elen);
+ p += zipPrevEncodeLength(p,prevlen);
+ p += zipEncodeLength(p,encoding,slen);
if (encoding != ZIP_ENC_RAW) {
zipSaveInteger(p,value,encoding);
} else {
- memcpy(p,entry,elen);
+ memcpy(p,s,slen);
}
ZIPLIST_INCR_LENGTH(zl,1);
return zl;
}
+unsigned char *ziplistPush(unsigned char *zl, char *s, unsigned int slen, int where) {
+ unsigned char *p;
+ p = (where == ZIPLIST_HEAD) ? ZIPLIST_ENTRY_HEAD(zl) : ZIPLIST_ENTRY_END(zl);
+ return __ziplistInsert(zl,p,s,slen);
+}
+
unsigned char *ziplistPop(unsigned char *zl, sds *target, int where) {
zlentry entry;
unsigned char *p;
if (target) *target = NULL;
/* Get pointer to element to remove */
- p = (where == ZIPLIST_HEAD) ? ziplistHead(zl) : ziplistTail(zl);
+ p = (where == ZIPLIST_HEAD) ? ZIPLIST_ENTRY_HEAD(zl) : ZIPLIST_ENTRY_TAIL(zl);
if (*p == ZIP_END) return zl;
entry = zipEntry(p);
return zl;
}
-/* Returns an offset to use for iterating with ziplistNext. */
-unsigned char *ziplistIndex(unsigned char *zl, unsigned int index) {
- unsigned char *p = zl+ZIPLIST_HEADER_SIZE;
- unsigned int i = 0;
- for (; i < index; i++) {
- if (*p == ZIP_END) break;
- p += zipRawEntryLength(p);
+/* Returns an offset to use for iterating with ziplistNext. When the given
+ * index is negative, the list is traversed back to front. When the list
+ * doesn't contain an element at the provided index, NULL is returned. */
+unsigned char *ziplistIndex(unsigned char *zl, int index) {
+ unsigned char *p;
+ zlentry entry;
+ if (index < 0) {
+ index = (-index)-1;
+ p = ZIPLIST_ENTRY_TAIL(zl);
+ if (p[0] != ZIP_END) {
+ entry = zipEntry(p);
+ while (entry.prevrawlen > 0 && index--) {
+ p -= entry.prevrawlen;
+ entry = zipEntry(p);
+ }
+ }
+ } else {
+ p = ZIPLIST_ENTRY_HEAD(zl);
+ while (p[0] != ZIP_END && index--) {
+ p += zipRawEntryLength(p);
+ }
}
- return p;
+ return (p[0] == ZIP_END || index > 0) ? NULL : p;
}
/* Return pointer to next entry in ziplist. */
unsigned char *ziplistNext(unsigned char *p) {
- return *p == ZIP_END ? p : p+zipRawEntryLength(p);
+ return (p[0] == ZIP_END) ? NULL : p+zipRawEntryLength(p);
+}
+
+/* Return pointer to previous entry in ziplist. */
+unsigned char *ziplistPrev(unsigned char *p) {
+ zlentry entry = zipEntry(p);
+ return (entry.prevrawlen == 0) ? NULL : p-entry.prevrawlen;
}
/* Get entry pointer to by 'p' and store in either 'e' or 'v' depending
* on the encoding of the entry. 'e' is always set to NULL to be able
* to find out whether the string pointer or the integer value was set.
* Return 0 if 'p' points to the end of the zipmap, 1 otherwise. */
-unsigned int ziplistGet(unsigned char *p, unsigned char **sstr, unsigned int *slen, long long *sval) {
+unsigned int ziplistGet(unsigned char *p, char **sstr, unsigned int *slen, long long *sval) {
zlentry entry;
- if (*p == ZIP_END) return 0;
+ if (p == NULL || p[0] == ZIP_END) return 0;
if (sstr) *sstr = NULL;
entry = zipEntry(p);
if (entry.encoding == ZIP_ENC_RAW) {
if (sstr) {
*slen = entry.len;
- *sstr = p+entry.headersize;
+ *sstr = (char*)p+entry.headersize;
}
} else {
if (sval) {
return 1;
}
-/* Delete a range of entries from the ziplist. */
-unsigned char *ziplistDeleteRange(unsigned char *zl, unsigned int index, unsigned int num) {
- unsigned char *p = ziplistIndex(zl,index);
- return __ziplistDelete(zl,p,num);
+/* Insert an entry at "p". */
+unsigned char *ziplistInsert(unsigned char *zl, unsigned char *p, char *s, unsigned int slen) {
+ return __ziplistInsert(zl,p,s,slen);
}
/* Delete a single entry from the ziplist, pointed to by *p.
* Also update *p in place, to be able to iterate over the
* ziplist, while deleting entries. */
-unsigned char *ziplistDelete(unsigned char *zl, unsigned char **p) {
+unsigned char *ziplistDelete(unsigned char *zl, unsigned char **p, int direction) {
unsigned int offset = *p-zl;
zl = __ziplistDelete(zl,*p,1);
/* Store pointer to current element in p, because ziplistDelete will
- * do a realloc which might result in a different "zl"-pointer. */
- *p = zl+offset;
+ * do a realloc which might result in a different "zl"-pointer.
+ * When the delete direction is back to front, we might delete the last
+ * entry and end up with "p" pointing to ZIP_END, so check this. */
+ if (*(zl+offset) == ZIP_END && direction == ZIPLIST_HEAD) {
+ *p = ZIPLIST_ENTRY_TAIL(zl);
+ } else {
+ *p = zl+offset;
+ }
return zl;
}
+/* Delete a range of entries from the ziplist. */
+unsigned char *ziplistDeleteRange(unsigned char *zl, unsigned int index, unsigned int num) {
+ unsigned char *p = ziplistIndex(zl,index);
+ return (p == NULL) ? zl : __ziplistDelete(zl,p,num);
+}
+
/* Compare entry pointer to by 'p' with 'entry'. Return 1 if equal. */
-unsigned int ziplistCompare(unsigned char *p, unsigned char *sstr, unsigned int slen) {
+unsigned int ziplistCompare(unsigned char *p, char *sstr, unsigned int slen) {
zlentry entry;
- unsigned char sencoding;
+ char sencoding;
long long val, sval;
- if (*p == ZIP_END) return 0;
+ if (p[0] == ZIP_END) return 0;
entry = zipEntry(p);
if (entry.encoding == ZIP_ENC_RAW) {
zlentry entry;
printf("{total bytes %d} {length %u}\n",ZIPLIST_BYTES(zl), ZIPLIST_LENGTH(zl));
- p = ziplistHead(zl);
+ p = ZIPLIST_ENTRY_HEAD(zl);
while(*p != ZIP_END) {
entry = zipEntry(p);
printf("{offset %ld, header %u, payload %u} ",p-zl,entry.headersize,entry.len);
unsigned char *createList() {
unsigned char *zl = ziplistNew();
- zl = ziplistPush(zl, (unsigned char*)"foo", 3, ZIPLIST_TAIL);
- zl = ziplistPush(zl, (unsigned char*)"quux", 4, ZIPLIST_TAIL);
- zl = ziplistPush(zl, (unsigned char*)"hello", 5, ZIPLIST_HEAD);
- zl = ziplistPush(zl, (unsigned char*)"1024", 4, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, "foo", 3, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, "quux", 4, ZIPLIST_TAIL);
+ zl = ziplistPush(zl, "hello", 5, ZIPLIST_HEAD);
+ zl = ziplistPush(zl, "1024", 4, ZIPLIST_TAIL);
return zl;
}
}
int main(int argc, char **argv) {
- unsigned char *zl, *p, *q, *entry;
+ unsigned char *zl, *p;
+ char *entry;
unsigned int elen;
long long value;
sds s;
printf("Pop tail: %s (length %ld)\n", s, sdslen(s));
ziplistRepr(zl);
+ printf("Get element at index 3:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 3);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index 3\n");
+ return 1;
+ }
+ if (entry) {
+ fwrite(entry,elen,1,stdout);
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ }
+
+ printf("Get element at index 4 (out of range):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, 4);
+ if (p == NULL) {
+ printf("No entry\n");
+ } else {
+ printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", p-zl);
+ return 1;
+ }
+ printf("\n");
+ }
+
+ printf("Get element at index -1 (last element):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index -1\n");
+ return 1;
+ }
+ if (entry) {
+ fwrite(entry,elen,1,stdout);
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ }
+
+ printf("Get element at index -4 (first element):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -4);
+ if (!ziplistGet(p, &entry, &elen, &value)) {
+ printf("ERROR: Could not access index -4\n");
+ return 1;
+ }
+ if (entry) {
+ fwrite(entry,elen,1,stdout);
+ printf("\n");
+ } else {
+ printf("%lld\n", value);
+ }
+ printf("\n");
+ }
+
+ printf("Get element at index -5 (reverse out of range):\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -5);
+ if (p == NULL) {
+ printf("No entry\n");
+ } else {
+ printf("ERROR: Out of range index should return NULL, returned offset: %ld\n", p-zl);
+ return 1;
+ }
+ printf("\n");
+ }
+
printf("Iterate list from 0 to end:\n");
{
zl = createList();
printf("\n");
}
+ printf("Iterate from back to front:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ fwrite(entry,elen,1,stdout);
+ } else {
+ printf("%lld", value);
+ }
+ p = ziplistPrev(p);
+ printf("\n");
+ }
+ printf("\n");
+ }
+
+ printf("Iterate from back to front, deleting all items:\n");
+ {
+ zl = createList();
+ p = ziplistIndex(zl, -1);
+ while (ziplistGet(p, &entry, &elen, &value)) {
+ printf("Entry: ");
+ if (entry) {
+ fwrite(entry,elen,1,stdout);
+ } else {
+ printf("%lld", value);
+ }
+ zl = ziplistDelete(zl, &p, ZIPLIST_HEAD);
+ printf("\n");
+ }
+ printf("\n");
+ }
+
printf("Delete inclusive range 0,0:\n");
{
zl = createList();
while (ziplistGet(p, &entry, &elen, &value)) {
if (entry && strncmp("foo", entry, elen) == 0) {
printf("Delete foo\n");
- zl = ziplistDelete(zl, &p);
+ zl = ziplistDelete(zl, &p, ZIPLIST_TAIL);
} else {
printf("Entry: ");
if (entry) {
p = ziplistIndex(zl, 0);
if (!ziplistCompare(p,"hello",5)) {
printf("ERROR: not \"hello\"\n");
- return;
+ return 1;
}
if (ziplistCompare(p,"hella",5)) {
printf("ERROR: \"hella\"\n");
- return;
+ return 1;
}
p = ziplistIndex(zl, 3);
if (!ziplistCompare(p,"1024",4)) {
printf("ERROR: not \"1024\"\n");
- return;
+ return 1;
}
if (ziplistCompare(p,"1025",4)) {
printf("ERROR: \"1025\"\n");
- return;
+ return 1;
}
printf("SUCCESS\n");
}
projects / redis.git / blobdiff